1. Field of the Invention
This invention relates to a control method for an outside control type fan coupling apparatus of such a type that, in general, rotational speed of a fan for use in cooling an engine in an automobile etc. is controlled by following temperature change in outside circumstance or rotation change.
2. Description of the Related Art
In the past, as this kind of fan coupling apparatuses, there is one of such a structure that, in such a system that an inside of a sealed housing comprising a case and a cover is divided into an oil holding chamber and a torque transmission chamber in which a drive disc is mounted by a partition plate which has an oil supply adjustment hole, and a dam and a circulation flow path which is strung to this and comes over from the torque transmission chamber side to the oil holding chamber are formed in a part of an inside wall of the sealed housing side which holds the oil at the time of rotation and opposes to an outside wall of the drive disc, and disposed is such a valve member that when temperature of outside circumstance exceeds a set value, the supply adjustment hole of the partition plate is opened and when it is less than the set value, the supply adjustment hole is closed, and torque transmission from a driving side to the sealed housing side of a driven side is controlled by increasing and decreasing an effective contact area of oil at a torque transmission gap part which is formed at an opposed wall surface of an outside vicinity of the drive disc and the sealed housing, a pair of electromagnets are disposed at a front surface side or a back surface side of the sealed housing, and, in opposition to one electromagnet, a valve member having magnetization for opening and closing the supply adjustment hole is disposed, or, in opposition to the other electromagnet, a sub-valve member having magnetization for opening and closing the circular flow path is disposed (See, U.S. Pat. No. 2,911,623).
Also, in the JP-A-9-119455 gazette, a viscous fluid joint which transmits output drive torque to an radiator cooling fan by drive torque from an engine of a vehicle and a control method thereof are disclosed. This viscous fluid joint is of such a system that, by transformation of a bimetal which responds to temperature of wind passing through the radiator, a valve is opened and closed so that oil supply quantity is varied and fan rotation is changed.
However, the outside control type fan coupling apparatus of the former has such drawbacks that it is of a complicated structure since generally, electric control takes the lead therein, and it needs large electric power consumption, and it is expensive, and also, in case that an electric system brakes down, operating oil stops its circulation so that the fan coupling apparatus becomes severely damaged. However, since the outside control type tan coupling apparatus has such advantages that it is possible to arbitrarily select water temperature, engine rotational speed, and control factors of auxiliary machine class etc. such as an air conditioner etc., and pertinent fan control can be carried out, improvement for eliminating the above-described drawbacks has been expected.
On one hand, in the cooling method of the latter which relies on only the temperature of wind passing through the radiator, there are such drawbacks that, since it is not possible to have the temperature of the radiator coolant which affects engine cooling performance as a direct controlled object, horsepower is lost due to unnecessary fan rotation, which leads to aggravation of fuel consumption, and also, it is not possible to maintain fan rotation which is good for cooling efficiency of a condenser of the air conditioner, and further, it is not possible to suppress fan noises due to unnecessary fan coupling rotation at the time of acceleration.
This invention is made to solve the above-described problems of the conventional technology, and in particular, proposes a control method for an outside control type fan coupling apparatus in which it is possible to always control the temperature of the radiator coolant to a range of good engine efficiency, and engine performance and fuel consumption are improved, and also, cooling efficiency of the air conditioner can be improved and good fan rotation can be maintained, and further, the coupling rotation at the time of acceleration is prevented and the fan noises can be reduced.
Inventors of this invention, in light of the problems of the conventional technology, proposed in advance an outside control type fan coupling apparatus which has a simple mechanism, and can save power consumption, and has a safety-On function (which mean that even if the electric system breaks down, the operating oil does not stop but circulates), and can control rotational speed of the fan arbitrarily and precisely by adjusting the oil quantity with a high degree of accuracy in compliance with various operational conditions (Japanese Patent Application 2001-190909).
This outside control type fan coupling apparatus is basically one which adopted a system of controlling a valve member for opening and closing an oil supply adjustment hole through which the operating oil is supplied from an oil holding chamber to a torque transmission chamber by a non-excitation type electromagnet using a permanent magnet, and concretely, in such a structure that an inside of a sealed housing comprising a case which is supported through a bearing on a rotation shaft to whose tip a drive disc is fixed and a cover which is attached to the case is divided into an oil holding chamber and a torque transmission chamber in which the drive disc is mounted by a partition plate which has an oil supply adjustment hole, a dam and a circulation flow path which is strung to this and comes over from the torque transmission chamber side to the oil holding chamber are formed in a part of an inside wall of the sealed housing side which holds the oil at the time of rotation and opposes to an outside wall of the drive disc, and a valve member for opening and closing the oil supply adjustment hole is disposed in the oil holding chamber, and made is such a system that a running torque transmission from a driving side to a driven side is controlled by increasing and decreasing an effective contact area of oil at a torque transmission gap part which is formed by the driving side and the driven side, and at the oil holding chamber side of the sealed housing, one which has such a structure that a non-excitation type electromagnet utilizing a permanent magnet is supported to the rotation shaft through the bearing, and the valve member is operated by the electromagnet and thereby, oil supply adjustment hole is controlled to be opened or closed, and, among them, especially one of such a double valve structure that a plurality of the oil supply adjustment holes are disposed, and an On use valve and a Middle use valve in which the valve member and the non-excitation type electromagnet are disposed with respect to each oil supply adjustment hole are disposed excels at such a point that, since each valve can be opened and closed in steps by changing size of electric current which flows through the electromagnet in steps, the fan rotation can be increased in steps, or increasing speed can be changed.
This invention is one for 3 step On/Off control method, which tries to propose more concrete and various control methods of this outside control type fan coupling apparatus of the double valve structure, and its first control method is of such a substance that when a vehicle moves, acceleration of an engine is detected, and when the acceleration is larger than a set value, the On use valve and the Middle use valve are closed to make the fan Off rotation, and when the acceleration is smaller than the set value, temperature of engine coolant is detected, and when the coolant temperature is smaller than a lower limit threshold value, operating conditions of an air conditioner is detected, and when the air conditioner does not operate, the On use valve and the Middle use valve are closed to make the fan Off rotation, and when the air conditioner operates, the On use valve is closed and the Middle use valve is opened to make the fan Middle rotation, and on the other hand, when the coolant temperature is larger than the lower limit threshold value and smaller than the upper limit threshold value, the On use valve is closed and the Middle use valve is opened to make the fan Middle rotation, and when the coolant temperature is larger than the upper limit threshold value, the engine rotational speed at that time is detected, and in case that the rotational speed is smaller than the lower limit engine rotational speed for making the fan On rotation, the On use valve is closed and the Middle use valve is opened to make the fan Middle rotation, and in case that it is larger than the lower limit engine rotational speed, the On use valve and the Middle use valve is opened, or only the On use valve is opened to make the fan On rotation, and when the engine stops, the On use valve and the Middle use valve are closed to make the fan Off rotation.
A second control method is of such a substance of 5 steps on/Off switching control method that, when a vehicle moves, an acceleration of an engine is detected, and when the acceleration is larger than a set value, the On use valve and the Middle use valve are closed to make a fan Off rotation, and when the acceleration is smaller than the set value, engine coolant temperature is detected, and when the coolant temperature is smaller than a lower limit threshold value, an operational state of an air conditioner is detected, and when the air conditioner does not operate, the On use valve and the Middle use valve are closed to make the fan Off rotation, and when the air conditioner operates, the On use valve is closed and the Middle use valve is opened and closed to make the fan Off rotationxe2x80x94Middle rotation, and on the other hand, when the coolant temperature is larger than the lower limit threshold value and smaller than an upper limit threshold value, the coolant temperature is compared to a middle low threshold value, and when the coolant temperature is lower than the middle low threshold value, the On use valve is closed and the Middle use valve is opened to make the fan Middle rotation, and when the coolant temperature is larger than a middle high threshold value, rotational speed of the engine at that time is detected, and in case that the rotational speed is smaller than a lower limit engine rotational speed for making the fan On rotation, the On use valve is closed and the Middle use valve is opened to make the fan Middle rotation, and in case that it is larger than the lower limit engine rotational speed, the coolant temperature at that time is detected, and the coolant temperature is compared to the upper limit threshold value, and when the coolant temperature is smaller than the upper limit threshold value, the Middle use value is closed, or the Middle use valve is opened, and the On use valve is opened and closed, or the Middle use valve is opened, and the On use valve is opened and closed to make the fan Middle rotationxe2x80x94On rotation, and when it is larger than the upper limit threshold value, the On use valve and the Middle use valve are opened to make the fan On rotation, and when the engine stops, the On use valve and the Middle use valve are closed to make the fan Off rotation.
A third control method is of such a substance of a step-less switching control method that when a vehicle moves, a fan rotation set value is determined on the basis of temperature of engine coolant, temperature of transmission oil, intake air temperature, compressor pressure of an air conditioner, and vehicle speed, and further, on the basis of the engine rotational speed, fan On rotational speed and fan Middle rotational speed are determined, and when acceleration of the engine is larger than the set value, the On use valve and the Middle use valve are closed to make the fan Off rotation, and when the acceleration is smaller than the set value, the engine rotational speed is detected, and when the rotational speed is smaller than a lower limit engine rotational speed for making the fan On rotation, the temperature of engine coolant is detected, when the temperature of the coolant is lower than the lower limit threshold valve, the On use valve and the Middle use valve are closed to make the fan Off rotation, and when the temperature of engine coolant is larger than the lower limit threshold value, the temperature of engine coolant is detected, when the temperature of the coolant is lower than the lower limit threshold valve, the On use valve is closed and the Middle use valve is opened to have Middle rotation, and when the engine rotational speed is larger than the lower limit engine rotational speed for making the fan On rotation, the fan On rotational speed is compared to the fan rotation set value, and when the fan On rotational speed is smaller than the fan rotation set value, the On use valve and the Middle use valve are opened to make the fan on rotation, and when the fan On rotational speed is larger than the fan rotation set value, the lower limit engine rotational speed for making the fan On rotation is compared to the fan rotation set value, and when the lower limit engine rotational speed for making the fan On rotation is smaller than the fan rotation set value, the fan rotational speed is detected, and when the rotational speed is larger than the fan rotation set value, the On use valve is closed and the Middle use valve is opened to make the fan Middle rotationxe2x80x94On rotation, and when the fan rotational speed is smaller than the fan rotation set value, the On use valve and the Middle use valve are opened to make the fan Middle rotationxe2x80x94On rotation, and when the lower limit engine rotational speed for making the fan On rotation is larger than the fan rotation set value, the fan rotational speed is detected, and when the rotational speed is larger than the fan rotation set value, the On use valve and the Middle use valve are closed to make the fan Off rotationxe2x80x94Middle rotation, and when the fan rotational speed is smaller than the fan rotation set value, the On use valve is closed and the Middle use valve is opened to make the fan Off rotationxe2x80x94Middle rotation, and when the engine stops, the On use valve and the Middle use valve are closed to make the fan Off rotation.
A fourth control method is of such a substance of step-less switching control method that when a vehicle moves, a fan rotation set value is determined on the basis of temperature of engine coolant, temperature of transmission oil, intake air temperature, compressor pressure of an air conditioner, and vehicle speed, and further, on the basis of the engine rotational speed, fan On rotational speed and fan Middle rotational speed are determined, and when acceleration of the engine is larger than the set value, the On use valve and the Middle use valve are closed to make the fan Off rotation, and when the acceleration is smaller than the set value, the engine rotational speed is detected, and when the rotational speed is smaller than a lower limit engine rotational speed for making the fan On rotation, the temperature of engine coolant is detected, when the temperature of the coolant is less than the lower limit threshold valve, the On use valve and the Middle use valve are closed to make the fan Off rotation, and when the temperature of engine coolant is larger than the lower limit threshold value, the On use valve is closed and the Middle use valve is opened to have Middle rotation, and when the engine rotational speed is larger than the lower limit engine rotational speed for making the fan On rotation, the fan on rotational speed is compared to the fan rotation set value, and when the fan On rotational speed is smaller than the fan rotation set value, the On use valve and the Middle use valve are opened, to make the fan On rotation, and when the fan on rotational speed is larger than the fan rotation set value, the fan Middle rotational speed is compared to the fan rotation set value, and when the fan Middle rotational speed is smaller than the fan rotation set value, the fan rotational speed is detected, and when the rotational speed is smaller than the a lower limit of the fan rotation set value, the On use valve is opened at a set opening rate, and the Middle use valve is closed, or the Middle use valve is opened to make the fan Middle rotationxe2x80x94On rotation, and when the fan rotational speed is larger than the lower limit of the fan rotation set value, the fan rotational speed is compared to the upper limit of the fan rotation set value, and when the fan rotational speed is larger than the upper limit of the fan rotation set value, the On use valve is opened at the set opening rate, and the Middle use valve is closed, or the Middle use valve is opened to make the fan Middle rotationxe2x80x94On rotation, and when the fan rotational speed is smaller than the upper limit of the fan rotation set value, the On use valve is opened at the set opening rate, and the Middle use valve is closed, or the Middle use valve is opened to make the fan Middle rotationxe2x80x94On rotation, and when the fan Middle rotational speed is larger than the fan rotation set value, the fan rotational speed is detected, and when the rotational speed is smaller than the lower limit of the fan rotation set value, the On use valve is closed, and the Middle use valve is opened at the set opening rate to make the fan Off rotationxe2x80x94Middle rotation, and when the fan rotational speed is larger than the lower limit of the fan rotation set value, the fan rotational speed is compared to the upper limit of the fan rotation set value, and when the fan rotational speed is larger than the upper limit of the fan rotation set value, the On use valve is closed, and the Middle use valve is opened at the set opening rate to make the fan Off rotationxe2x80x94Middle rotation, and when the fan rotational speed is smaller than the upper limit of the fan rotation set value, the On use valve is closed and the Middle use valve is opened at the set opening rate to make the fan Off rotationxe2x80x94Middle rotation, and when the engine stops, the On use valve and the Middle use valve are closed to make the fan Off rotation.
It is of such a substance of a 3 step On/Off control method that the set opening rates of the On use valve and the Middle use valve are set to full-time 100% full-open, respectively so that a control characteristic of the fan is controlled by 3 steps of Off rotation, Middle rotation, and On rotation.
It is of such a substance of a 5 step switching control method that the set opening rates of the On use valve and the Middle use valve are set to constant opening rates respectively so that a control characteristic of the fan is controlled by 5 steps of Off rotation, Off rotationxe2x80x94Middle rotation, Middle rotation, Middle rotationxe2x80x94On rotation, and On rotation.
It is of such a substance of a step-less On/Off control method that when a vehicle moves, a fan rotation set value is determined on the basis of temperature of engine coolant, temperature of transmission oil, intake air temperature, compressor pressure of an air conditioner, and vehicle speed, and further, on the basis of the engine rotational speed, fan On rotational speed and fan Middle rotational speed are determined, and when acceleration of the engine is larger than the set value, the On use valve and the Middle use valve are closed to make the fan Off rotation, and when the acceleration is smaller than the set value, the engine rotational speed is detected, and when the rotational speed is smaller than a lower limit engine rotational speed for making the fan On rotation, the temperature of engine coolant is detected, when the temperature of the coolant is lower than the lower limit threshold valve, the On use valve and the Middle use valve are closed to make the fan Off rotation, and when the temperature of engine coolant is larger than the lower limit threshold value, the On use valve is closed and the Middle use valve is opened to have Middle rotation, and when the engine rotational speed is larger than the lower limit engine rotational speed for making the fan On rotation, the fan On rotational speed is compared to the fan rotation set value, and when the fan On rotational speed is smaller than the fan rotation set value, the On use valve and the Middle use valve are opened, to make the fan On rotation, and when the fan On rotational speed is larger than the fan rotation set value, the fan Middle rotational speed is compared to the fan rotation set value, and when the fan Middle rotational speed is smaller than the fan rotation set value, the fan rotational speed is detected, and when the rotational speed is smaller than a certain set value, the On use valve is fully opened and the Middle use valve is closed, or the Middle use valve is opened to make the fan Middle rotationxe2x80x94On rotation, and when the fan rotational speed is larger than the certain set value, the On use valve is fully opened and the Middle use valve is closed, or the Middle use valve is opened to make the fan Middle rotationxe2x80x94On rotation, and when the fan Middle rotational speed is larger than the fan rotation set value, the fan rotational speed is detected, and when the rotational speed is smaller than the certain set value, the On use valve is closed and the Middle use valve is fully opened to make the fan Off rotationxe2x80x94Middle rotation, and when the fan rotational speed is larger than the certain set value, the On use valve and the Middle use valve are closed to make the fan Off rotationxe2x80x94Middle rotation, and when the engine stops, the On use valve and the Middle use valve are closed to make the fan Off rotation.